Balancing a cylinder on a thin vertical layer of viscous fluid.

We analyze recent experiments that show that a cylinder can be suspended in a stable position by placing it on a vertically moving belt that is covered by a thin layer of very viscous oil. The weight of the cylinder is supported by viscous forces in the fluid layer, and the cylinder rotates with respect to its axis in the direction of the belt motion. We propose a simple model for stable suspension of the cylinder, based on lubrication ideas.